New Insights into Language Processing and Change By Investigating Tactile Sign Language

Extensive research over many decades has illuminated the human capacity for language through the study of spoken languages. In the past 20 years research into visual sign languages have provided us with important and unique insights into human language that could not have been obtained by studying spoken languages alone (Emmorey, 2023). For example, we now know that visual sign languages are just as linguistically complex as spoken languages and that developmental and/or acquired language disorders can impact visual sign language perception, production and processing (Mason et al., 2010). We also know that areas in the brain used for spoken language processing are also recruited for visual sign language processing (MacSweeney et al., 2008). Language can also be perceived through touch: the tactile modality. Some deafblind individuals communicate using tactile sign language, as spoken and visual sign languages may be inaccessible for them. There is some linguistic documentation of tactile sign language in countries such as Sweden (Mesch, 2001), the USA (Edwards, 2017) and India (Kusters, 2017). There is still a dearth of research on tactile sign language in the U.K, and worldwide, and compared to spoken and visual sign languages (Simcock et al, 2024). Studying tactile sign language may lead to valuable insights into the nature of human language. This deeper understanding of tactile sign language will enhance our ability to support deafblind individuals and promote their fuller participation in society. To gain those insights, I propose a novel, multidisciplinary and ground-breaking approach where I will document tactile sign language in British deafblind individuals using linguistic ethnography and corpus linguistics methodologies. I will also use a state-of-the-art functional Near-Infrared Spectroscopy (fNIRS), to explore whether the classical areas for processing spoken and visual sign languages are also used for tactile sign language processing.